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Algebraic data types: Difference between revisions
→{{header|REXX}}: added the REXX language.
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rascal>/a.c/ := "abc";
bool: true</lang>
=={{header|REXX}}==
The nodes used for this example are taken from the Wikipedia example at:
[[https://en.wikipedia.org/wiki/Red%E2%80%93black_tree#/media/File:Red-black_tree_example.svg red black tree, an example]]
<lang rexx>/*REXX pgm builds a red/black tree (with verification & validation), balances as needed.*/
parse arg nodes '/' insert /*obtain optional arguments from the CL*/
if nodes='' then nodes = 13.8.17 8.1.11 17.15.25 1.6 25.22.27 /*default nodes.*/
if insert='' then insert= 22.44 44.66 /* " inserts*/
top=.
call Dnodes nodes /*define nodes, balance them as added. */
call Dnodes insert /*insert nodes, balance them as needed.*/
call Lnodes /*list the nodes (with indentation). */
exit /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
Dnodes: arg $d; do j=1 for words($d); t=word($d, j) /*color: encoded into LEV.*/
parse var t p '.' a "." b '.' x 1 . . . xx
call Vnodes p a b
if x\=='' then call err "too many nodes specified: " xx
if p\==top then if @.p==. then call err "node isn't defined: " p
if p ==top then do; !.p=1; L.1=p; end /*assign the top node. */
@.p=a b; n=!.p + 1 /*assign node; bump level.*/
if a\=='' then do; !.a=n; @.a=; maxL=max(maxL, !.a); end
if b\=='' then do; !.b=n; @.b=; maxL=max(maxL, !.b); end
L.n=space(L.n a b) /*append to the level list*/
end /*j*/
return
/*──────────────────────────────────────────────────────────────────────────────────────*/
err: say; say '***error***: ' arg(1); say; exit 13
/*──────────────────────────────────────────────────────────────────────────────────────*/
Lnodes: do L=1 for maxL; w=length(maxL); rb=word('(red) (black)', 1 + L//2)
say "level:" right(L, w) left('', L+L) " ───► " rb ' ' L.L
end /*lev*/
return
/*──────────────────────────────────────────────────────────────────────────────────────*/
Vnodes: arg $v; do v=1 for words($v); y=word($v, v)
if \datatype(y, 'W') then call err "node isn't a whole number: " y
y=y/1 /*normalize the Y integer: no LZ, dot*/
if top==. then do; LO=y; top=y; HI=y; L.=; @.=; maxL=1; end
LO=min(LO, y); HI=max(HI, y)
if @.y\==. & @.y\=='' then call err "node is already defined: " y
end /*v*/
return</lang> <br><br>
=={{header|Rust}}==
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}
}
}</lang>
=={{header|Scala}}==
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